BFilter

BFilter is a smart filtering HTTP proxy. Its primary purpose is removing banner ads. Unlike the majority of similar tools, it doesn't rely on a list of blocked URLs, but instead parses HTML on the fly, and detects ads using a set of heuristic rules. BFilter has a built-in Javascript engine that detects js-generated ads.

Release Notes: It's now possible to have multiple forwarding
configurations, switch
between them with two clicks, and manage them in a
GUI. Forwarding to a
chain of proxies has been implemented. HTTPS hosts
can now be (manually)
blocked. Ad detection accuracy has been improved.
A crash in the GTK GUI
has been fixed.